Silicone surfactants have been designed for various applications by combining a hydrophobic organopolysiloxane with various hydrophilic moieties. For example, the silicone surfactants known as silicone polyethers are based on copolymer structures of polydimethylsiloxane having pendant polyoxyalkylene groups. Such materials find wide utility in many personal, household, and health care compositions as emulsifiers, wetting agents, and general-purpose aqueous surfactants.
The aggregation behavior of silicone polyethers has been discussed along with their ability to form vesicles. For example, U.S. Pat. Nos. 5,364,633 and 5,411,744 by Hill teaches the self-assembly of silicone vesicles in aqueous dispersions of certain silicone polyethers. PCT application US03/38455 by Lin teaches the entrapment of various oils in silicone vesicles and their use in various personal care formulations.
While these references represent advancements in the art, a need still exists to create silicone vesicles having improved stability. For example, the silicone vesicles formed from the self-assembly procedures can lack durability. This lack of durability can limit the processing conditions they can be subject to in the formation of various finished products. Furthermore, such self-assembled silicone vesicles can lack the ability to provide sustained protection of loaded actives over an extended period of time. Thus, a need exists for a process to prepare silicone vesicles having improved stability and the ability to protect loaded actives over an extended period of time.
The present inventors have discovered a process to prepare silicone vesicles having improved stability and the ability to protect loaded actives over an extended period of time.